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/*
* Copyright (c) 2007 Bobby Bingham
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdint.h>
#include "scale_eval.h"
#include "libavutil/eval.h"
#include "libavutil/mathematics.h"
#include "libavutil/pixdesc.h"
static const char *const var_names[] = {
"in_w", "iw",
"in_h", "ih",
"out_w", "ow",
"out_h", "oh",
"a",
"sar",
"dar",
"hsub",
"vsub",
"ohsub",
"ovsub",
NULL
};
enum var_name {
VAR_IN_W, VAR_IW,
VAR_IN_H, VAR_IH,
VAR_OUT_W, VAR_OW,
VAR_OUT_H, VAR_OH,
VAR_A,
VAR_SAR,
VAR_DAR,
VAR_HSUB,
VAR_VSUB,
VAR_OHSUB,
VAR_OVSUB,
VARS_NB
};
int ff_scale_eval_dimensions(void *log_ctx,
const char *w_expr, const char *h_expr,
AVFilterLink *inlink, AVFilterLink *outlink,
int *ret_w, int *ret_h)
{
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
const AVPixFmtDescriptor *out_desc = av_pix_fmt_desc_get(outlink->format);
const char *expr;
int eval_w, eval_h;
int ret;
double var_values[VARS_NB], res;
var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w;
var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h;
var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
var_values[VAR_A] = (double) inlink->w / inlink->h;
var_values[VAR_SAR] = inlink->sample_aspect_ratio.num ?
(double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
var_values[VAR_DAR] = var_values[VAR_A] * var_values[VAR_SAR];
var_values[VAR_HSUB] = 1 << desc->log2_chroma_w;
var_values[VAR_VSUB] = 1 << desc->log2_chroma_h;
var_values[VAR_OHSUB] = 1 << out_desc->log2_chroma_w;
var_values[VAR_OVSUB] = 1 << out_desc->log2_chroma_h;
/* evaluate width and height */
av_expr_parse_and_eval(&res, (expr = w_expr),
var_names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, log_ctx);
eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = (int) res == 0 ? inlink->w : (int) res;
if ((ret = av_expr_parse_and_eval(&res, (expr = h_expr),
var_names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
goto fail;
eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = (int) res == 0 ? inlink->h : (int) res;
/* evaluate again the width, as it may depend on the output height */
if ((ret = av_expr_parse_and_eval(&res, (expr = w_expr),
var_names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
goto fail;
eval_w = (int) res == 0 ? inlink->w : (int) res;
*ret_w = eval_w;
*ret_h = eval_h;
return 0;
fail:
av_log(log_ctx, AV_LOG_ERROR,
"Error when evaluating the expression '%s'.\n"
"Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
expr, w_expr, h_expr);
return ret;
}
int ff_scale_adjust_dimensions(AVFilterLink *inlink,
int *ret_w, int *ret_h,
int force_original_aspect_ratio, int force_divisible_by)
{
int w, h;
int factor_w, factor_h;
w = *ret_w;
h = *ret_h;
/* Check if it is requested that the result has to be divisible by some
* factor (w or h = -n with n being the factor). */
factor_w = 1;
factor_h = 1;
if (w < -1) {
factor_w = -w;
}
if (h < -1) {
factor_h = -h;
}
if (w < 0 && h < 0) {
w = inlink->w;
h = inlink->h;
}
/* Make sure that the result is divisible by the factor we determined
* earlier. If no factor was set, nothing will happen as the default
* factor is 1 */
if (w < 0)
w = av_rescale(h, inlink->w, inlink->h * factor_w) * factor_w;
if (h < 0)
h = av_rescale(w, inlink->h, inlink->w * factor_h) * factor_h;
/* Note that force_original_aspect_ratio may overwrite the previous set
* dimensions so that it is not divisible by the set factors anymore
* unless force_divisible_by is defined as well */
if (force_original_aspect_ratio) {
// Including force_divisible_by here rounds to the nearest multiple of it.
int tmp_w = av_rescale(h, inlink->w, inlink->h * (int64_t)force_divisible_by)
* force_divisible_by;
int tmp_h = av_rescale(w, inlink->h, inlink->w * (int64_t)force_divisible_by)
* force_divisible_by;
if (force_original_aspect_ratio == 1) {
w = FFMIN(tmp_w, w);
h = FFMIN(tmp_h, h);
if (force_divisible_by > 1) {
// round down in case provided w or h is not divisible.
w = w / force_divisible_by * force_divisible_by;
h = h / force_divisible_by * force_divisible_by;
}
} else {
w = FFMAX(tmp_w, w);
h = FFMAX(tmp_h, h);
if (force_divisible_by > 1) {
// round up in case provided w or h is not divisible.
w = (w + force_divisible_by - 1) / force_divisible_by * force_divisible_by;
h = (h + force_divisible_by - 1) / force_divisible_by * force_divisible_by;
}
}
}
*ret_w = w;
*ret_h = h;
return 0;
}
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